Choppy/delayed playback

Hello,

I recently upgrade my PC to:

P4 3.2GHZ
1024 XMS3500 RAM
RADEON 9800XT
2 WD 10k RAPTORS in RAID0

When I use Adobe Premiere to make PAL and NTSC videos playback is always choppy and delayed when I hit the play button or when I do anything to the timeline it freezes for 20-30 seconds before i can do anything. Its immensly anoying especialy since i bought a new pc to try and fix the problem.

anyway is the some type of DV card that uses hardware editing so playback will always be smooth and responsive?